Manganese(II,III) oxide is the chemical compound with formula Mn₃O₄.

Manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

is present in two

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

s +2 and +3 and the formula is sometimes written as MnO· Mn₂O₃. Mn₃O₄ is found in nature as the mineral

hausmannite Hausmannite is a complex oxide of manganese containing both di- and tri-valent manganese. The formula can be represented as Mn2+Mn3+2O4. It belongs to the spinel group and forms tetragonal crystals. Hausmannite is a brown to black metallic minera ...

Preparation

Mn₃O₄ formed when any manganese oxide is heated in air above 1000 °C. Considerable research has centred on producing

nanocrystal A ''nanocrystal'' is a material particle having at least one dimension smaller than 100 nanometres, based on quantum dots (a nanoparticle) and composed of atoms in either a single- or poly-crystalline arrangement. The size of nanocrystals dist ...

line Mn₃O₄ and various syntheses that involve oxidation of Mn^II or reduction of Mn^VI.

Reactions

Mn₃O₄ has been found to act as a catalyst for a range of reactions e.g. the oxidation of methane and carbon monoxide; the decomposition of NO, the reduction of nitrobenzene and the

catalytic combustion Catalytic combustion is a chemical process which uses a catalyst to speed desired oxidation reactions of fuel and so reduce the formation of undesired products, especially pollutant nitrogen oxide gases (NOx) far below what can be achieved without ...

of organic compounds.

Structure

Mn₃O₄ has the

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties S ...

structure, where the oxide ions are cubic close packed and the Mn^II occupy tetrahedral sites and the Mn^III octahedral sites. The structure is distorted due to the

Jahn–Teller effect The Jahn–Teller effect (JT effect or JTE) is an important mechanism of spontaneous symmetry breaking in molecular and solid-state systems which has far-reaching consequences in different fields, and is responsible for a variety of phenomena in sp ...

. At room temperature Mn₃O₄ is

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, d ...

, below 41-43 K, it is

ferrimagnetic A ferrimagnetic material is a material that has populations of atoms with opposing magnetic moments, as in antiferromagnetism, but these moments are unequal in magnitude so a spontaneous magnetization remains. This can for example occur when ...

although this has been reported as reducing in nanocrystalline samples to around 39 K.

Uses

Mn₃O₄ is sometimes used as a starting material in the production of soft ferrites e.g. manganese zinc ferrite, and lithium manganese oxide, used in lithium batteries.Process for preparing lithium manganese oxides, U.S Patent number: 6706443,(2004), Horst Krampitz, Gerhard Wohner Manganese tetroxide can also be used as a weighting agent while drilling reservoir sections in oil and gas wells.

References

{{oxygen compounds Manganese compounds Transition metal oxides Mixed valence compounds